The present invention relates to an apparatus, sometimes described as a carpet extractor, which applies a mixture of water and a cleaning liquid to a carpet, floor or other surface for washing the surface and loosening or dissolving dirt. A separate suction means is associated with the liquid supply. Through a suction nozzle, it suctions the liquid and the loosened or dissolved dirt off the carpet or surface.
Various surface cleaner and carpet extractor arrangements are known, which mix a cleaning liquid with water. They supply the surface cleaning carpet cleaning liquid or shampoo through a dispenser located at a manually operable control valve under the operation of the user. Some of these control valves are placed at the hand held hose or wand that supports both the mixed liquid spraying nozzle and the suction nozzle. Where the cleaning liquid is supplied through a control valve, a venturi arrangement may be used, where the water under pressure passes appropriately shaped passages that meet the water channel to create a venturi effect and suck in the required cleaning liquid.
Another arrangement provides a pre-mixed supply of liquid, consisting of mixed water and detergent. A pump connected with the spray nozzle pumps the pre-mixture to the spray nozzle. Yet another arrangement is in the garden spray type which pumps air under pressure into a tank of premixed water and cleaning liquid, and the liquid is then supplied under pressure.
The above systems are generally high pressure systems, not low pressure systems. This requires better valving, stronger and more expensive tubing, more expensive construction, and the like. A known venturi system could not be used in low pressure operations. It would not usually be possible to develop a sufficiently small orifice at the venturi to avoid back pressure of liquid flow. If the venturi is operable, then the flow of liquid might be insufficient.
Draining and depressurizing prior systems is another problem not adequately addressed. Usually, the user shuts off the standard continuous water supply and then releases the pressure by opening the normal outlet and dispensing valve. This requires either moving the outlet nozzle to a sink or having to clean or suction the extra liquid dispensed during pressure release. Avoidance of this problem is desirable.
Many of these apparatus provide a combination of a liquid supply and delivery means and a portable suction apparatus. The liquid supply means is supported on the suction apparatus. For example, liquid supply is from a tank of the liquid. In some arrangements, the liquid supply is not portable. Instead, there is a main liquid supply, such as a water line, and an elongate dispensing hose for dispensing liquid where it is needed, i.e. to a nozzle near the inlet to the suction apparatus.
The present invention is primarily directed to the latter type of carpet extractor or floor or surface cleaner. That type of cleaner uses a standard suction cleaner, such as a wet/dry pickup cleaner, having a suction nozzle for wet/dry pickup. Near the suction nozzle, there is also a liquid dispenser, and the liquid dispenser is connected by an elongate line to a supply of mixed water and detergent. The supply may be connected with a standard water line and the invention concerns means at the water line for mixing detergent with the liquid moving to the liquid dispenser at the suction nozzle.
Germeshausen, U.S. Pat. No. 3,155,113, shows a device located in a water line for mixing fertilizer in water, so that the combined water and fertilizer mixture may be dispensed. The water pressure in a chamber surrounding a flexible container of liquid fertilizer dispenses the water and the fertilizer into the outlet line in a preset ratio by volume and flow rate which is in part determined by the size of the metering orifices for the water and for the fertilizer. The unit in this patent is generally aligned in the water flow line, and is not offset to the side of the flow line. Further, no concern is taken as to the maintenance of a desired pressure level, that is other than by adjusting the outflow from the water source. Also, no means is disclosed for dealing with a sealed container of fluid to be mixed with the water.
Healy, U.S. Pat. No. 4,418,869 mixes a chemical with water by entraining some of the chemical expelled from a container. This patent does not utilize a flowing fluid, flowing between an outer container and an inner flexible container and then back into the water flow line to dispense from the inner container. Instead, the water under pressure that is disposed between the outer resilient container and the inner flexible container is static. Features relating to the invention that are absent from the Germeshausen patent are not supplied by the Healy patent.